Interlocking terminal block construction



v- 1955 A. H. STUB BERS INTERLOCKING TERMINAL BLOCK CONSTRUCTION 5 Sheets-Sheet 1 Filed Sept. 4, 1952 IN V EN TOR. Mud z WM, 154% {m ATTOkA/E Y 5.

V- 1955 A. H. STUBBERS INTERLOCK ING TERMINAL BLOCK CONSTRUCTION 5 Sheets-Sheet 2 Filed Sept. 4, 1952 IN V EN TOR BY 4 TTORNEYS.

NOV. 22, 1955 sT s 2,724,814

INTERLOCKING TERMINAL BLOCK CONSTRUCTION Filed Sept. 4, 1952 3 Sheets-Sheet 3 IN V EN TOR.

ATTORNE Y5- United States Patent INT RLO KIN G TERM AL BL C CONSTRUCTION Application September 4, 1952, Serial N 0. 307,940 6 Claims (Cl. 33 91 98) Th s nve ti n rela es to t rminal l k c ns ruc f he type comp is ng a n mber o indivi ual. or un blocks c a e ad p ed t be isp d r j ined in s by id re a io n u h c nstructi s, as m y i m d t th time of installa on, the umber of ni blocks selected for assembly being determined by the number of cross connections required at a given terminal.

The present invention is directed primarily to a simpliiled terminal block construction in which only three component elements are necessary, These elements are a metallic conductor piece, a unit insulator block, and a lock bar.

The invention concerns the construction of each of the component elements and their cooperation in assembly.

A pl r li y f ondu or, pi ces nd insulator blocks are utilized n a a embly, the number be g dependent upon the requirements of the particular installation.

However. nly ne look. bar is equired. Generally, ac Conductor piece c mpr a metall c mem er h ving endwise provisions for attaching wires, The insulator blocks are adapted respectively to receive the metallic conductor pieces and hold them in position. The blocks are assembled in side by side relation in a row, interlocking means being provided to insure perfect alignment. The lock bar is adapted to straddle and engage a plurality of insulator blocks so as to hold them in a row and also to engage the metallic conductors and restrain them against movement in the insulator blocks. With the lock bar in place, the assembly is self-sustaining so that it may be handled as if it were a one-piece terminal block construction.

One of the novel features which distinguishes this construction from those previously known, resides in the formation of the individual unit blocks. The unit blocks of the present invention are of duplicate configuration,

hence they may be used indiscriminately as end blocks or as conductor carrying blocks in an assembly. In this manner, specially designed end blocks as heretofore required, are not necessary, and assembly is materially simplified.

By virtue of the interlocking means and the lock bar, the tie bolts of conventional terminal block devices, which pass through all the blocks from one end of an assembly to the other, are eliminated. In contrast, the seated lock bar keys all blocks together. In addition however, it engages the metallic conductor pieces seated individually within the unit blocks and keys them in place. The entire assembly may be rigidly fastened to a panel board or the like merely by means of several screws or bolts placed in the ends of the lock bar. In one Sense therefore, the lock bar is the backbone of the assembly. Once it is secured, all blocks and all conductors within the blocks are firmly secured,

In addition to th s g neral prin ipl s, the c ns uelion embodies a number of specific features, which contribute to the overall improvement individually and collectively. These features are discussed in connection with the following detailed description of the drawings in which:

Figure l is a perspective view showing the three component elements comprising the terminal block construction of this invention.

Figure 2 is a perspective view showing the elements in assembly.

Figure 3 is a bottom in Figure 2.

Figure 4 is a side elevational view of the assembly.

Figure 5 is a cross section view taken on the line 5-5 in igure 2. t

Figure 6 is an enlarged cross sectional view taken on the line 66 in Figure 4.

Figure 7 is a fragmentary side elevational view illustrating a modified construction in which a different type of connector element is employed.

Figure 8 is a cross sectional view taken on the line 8.-8 in Figure 7.

Figure 9 is an enlarged fragmentary top plan view of the modified construction shown in Figures 7 and 8.

Figure 10 is a perspective view of a terminal block of modified construction.

Figure 11 is a perspective view showing the underside of a lock bar designed for use with the terminal lock. of Figur 1 Figure 12 is a perspective view of a conductor piece adapted to seat within the terminal block of Figure'lQ.

Figure 13 is a lateral cross sectional view through an assembly of the elements illustrated in Figures 10=-. 1 2.

The three component elements of the construction are shown in Figure 1. They comprise a unit insulator block a c nduc or pi c 11 and a P o o a ock. be 12. It is believed that the principles of the invention will be better un er t od f] he three omp nt eme t a e de i ed n detail p o to d scuss ng thei ooporation n as em y- 1 plan view of the assembly shown Unit insulator black It is p ferr ha a h f the n t. nsu ato blocks be of molded plastic construction. All of the blocks are of identical configuration, that is, there are no end blocks as such. The blocks at the two ends simply do not carry conductor pieces 11, as do all of the intermediate ones in an assembly. Each block is slotted longitudinally as at 13 to provide a seat for a conductor piece. In transverse cross section, therefore, each block is substantially U-shaped having a pair of upstanding side walls 14-14 which are joined by a base portion 15. In the central area of the block each side wall :14 has a rectangular notch 16 formed in its upper edge. The inner face of each side wall is also grooved vertically as at 17 in alignment with the notch 16, the groove extending substantially to the base portion 15 of the block. The two side edges of each groove 17 may be bevelled as at 18. The purpose of the notches and the grooves is to accommodate lock bar 12 which is to be described below. Grooves 17 also have a locking function with respect to the conductor piece, which will also be explained below.

At the respective sides of the base of each block, and adjacent opposite corners, rounded lugs, such as those shown at 20.20, are provided. Adjacent the other two corners, rounded recesses 21-21 are formed in the block. Each recess is aligned transversely with the lug on the opposite side of the block, and is of complementary configuration. Thus, when a plurality of blocks is assembled in side by side relation the lugs engage in the recesses insuring exact longitudinal alignment.

The .upper face of the base portion 15 of the unit block may be raised as shown at 22 to provide a seat and are spaced apart equally.

0 for the conductor piece 11. The raised portion covers that area which is between grooves 17-17 in the central portion of the block base. A. hole 23 is formed in the center ofthe raised portion. This hole constitutes a partially formed bolt or screw receiving hole for fastening assembled blocks to a terminal board. The hole is completed on the job, but only in the event the block is to be used as an end block in an assembly. This will be discussed below. Instead of the specific configuration shown in Figure 6, a thin Web of plastic may be provided for sealing the hole, the Web being adapted to be knocked out in the event the hole is required for fastening purposes.

Conductor piece A preferred embodiment of the conductor piece is indicated at 11 in Figures l-6 of the drawings. This conductor is formed from a short length of copper tubing which is generally rectangular in cross section. At

each end the upper wall of the tube is drilled and tapped to receive a set screw 24. The electric leads or wires are secured to the conductor by slipping stripped ends into the respective ends of the tube and tightening the screws down upon them.

The central part of the tube is configurated to provide a land 25 which is designed to be engaged by the lock bar 12 in order to lock the piece in place in the block. It is suggested that the land he formed by a stamping or dieing operation in which the mid portion of the conductor is partially collapsed. By forming the land in this manner, a pair of bosses 26 is formed at the opposite sides of the conductor at the same time. These bosses fit the grooves 17 in the side walls of the block. The conductor piece is placed in the block from the top, being dropped into place with the bosses 26 engaged in grooves 17. Such engagement restrains longitudinal movement of the connector when it is in the block and resting upon the raised portion 22. It is preferred that the conductor pieces be shorter and less wide than the slots 13 in order to provide an air gap surrounding the respective ends of each conductor piece when seated within a block.

A modified form of conductor piece, which requires slight modification of the unit insulator block, is discussed below under a separate heading.

Lock bar Generally, the lock bar 12 is designed to straddle and engage a plurality of terminal blocks which are placed along side of one another. The lock bar may be molded from plastic insulating material in long lengths and then cut to size on the job as required. The underside of the lock bar is configurated to provide a plurality of transverse slots 27. These slots are all identical in size The distance between adjacent slots 27 corresponds to the distance between the opposing faces of the grooves 17 in a block. The width of each slot is approximately twice the wall thickness in a side wall of the block beneath a notch 16 plus slip-fit clearance. The distance between the upper edge of a slot 27 and the upper face of the lock bar corresponds to the depth of a notch 16. The depth of bar material between slots 27 corresponds to the distance between the upper surface of the land 25 of a conductor seated within a block and the upper edges of the side walls 14 of the block. Thus the lock bar is received in the face of an assembly of blocks with each slot 27 straddling a pair of adjacent walls at notches 16, and with the bar material between slots depending into the block within grooves 17, and with the bottom of the bar within each block resting upon the land of the conductor residing therein. Hence, the seating of the lock bar not only keys all of the blocks together in assembly, but it-also keys each of the conductors in place within the respective blocks. When thus seated, the assembly is self-sustaining, even prior to being secured to a terminal board.

A plurality of partially completed holes is also provided in the lock bar. In this instance, the holes extend into the bar from the bottom. One partially completed hole is provided between each slot 27. This leaves an unbroken upper surface on the look bar which may be used for penciling indicia to identify the electrical leads terminating in an assembly. To facilitate marking, it is preferred that the upper surface be roughened. A roughened mold wall may be provided for this purpose or the surface may be scratched or etched after the bar is molded.

Assembly Upon determining the number of cross connections required at a given terminal, the workman selects that number of conductor pieces, and that number plus two of unit blocks. The two extra blocks are used as end blocks and should be drilled or punched to complete the partial holes 23. The unit blocks are then aligned side by side in a row with the lugs 20 engaged in recesses 21. The conductor pieces may then be dropped into place in the intermediate blocks, and the lock bar cut to the required length. At this time the two partially completed holes at the ends of the lock bar should be drilled or knocked out. The lock bar is then seated in the face of the assembly as described above. When in place, the roughened face of the lock bar is flush with the aligned blocks and the holes at its ends are aligned with the holes 23 in the two blocks at the respective ends of the assembly. Screws or bolts 30 such as the ones shown in Figures 4 and 5 then may be slipped through the aligned holes for fastening the assembly to the terminal board. When the screws or bolts are tightened, the elements of the assembly are locked into a unitary structure in which all connectors and all blocks are securely fastened by the lock bar.

Modifications In the embodiment of the invention shown in Figures 7-9 the conductor piece comprises a flat strip 31. The unit block also is modified slightly in order to accommodate piece 31. The lock bar utilized is substantially the same as the one described above. The upper face of conductor 31 is punched at the center, as shown at 32 in Figure 8, to provide a circular boss 33 which protrudes from the bottom of the strip. This boss is the same diameter .as the partially completed hole 23 in the block base and adapted to be seated therein to restrain the conductor strip against lateral movement. The wire leads are connected to the respective ends of strip 31 by terminal screws 34 which thread into tapped holes in the respective ends of the strip. In order to accommodate the lower ends of the terminal screws, a well 35 is formed in the base of the block beneath each screw.

The grooves 17 of the embodiment discussed above may or may not be utilized. That is, they are not requisite for the successful functioning of the assembly. In the modification they are omitted, and thus the spacing and size of slots 27 in the lock bar are changed accordingly.

The sides of the conductor strip 31 in the end portions may be relieved as shown at 36 in Figure 9 to facilitate the insertion of the strip and provide an air gap, leaving only the central portion of the strip substantially the same size as the space between the side walls of the block to restrain the strip against turning in its seat. The strip conductors 31 of the modified form are keyed in place in the same way that the tubu lar conductors 11 are keyed. That is, the under surface of the lock bar between adjacent slots 27 rests directly upon the central portion. It will be seen that the design of the end portions of the connectors used in the assembly is not critical, and other means may be employed than those shown for attaching wires.

Figures -13 illustrate another modification embodying the principles of the invention in which a unit block 37, a lock bar 38 and a conductor piece 39 are employed. This embodiment differs from those discussed above. in the manner in which the conductor piece is Seated Within the. block and in the design of the lock bar. The conductor piece in this instance comprises a short length of copper tubing which is substantially rectangular in cross section. Terminal screws indicated at 40 are threaded into tapped bores adjacent the respective ends of each piece. A tang 41 is struck up from the bottom of the conductor piece midway between the two terminal screws to serve as a stop for the leads when they are inserted into the open ends of the tubing. Piece 39 is keyed to block 38 by means of a pair of dimples which are formed in the respective opposite lower edges of the section of tubing midway between its ends. The dimples 42 are designed to seat upon two small protuberances or lugs 43 which project toward one another from the lower edges of the side walls of the block at the center of the longitudinal slot therein. A raised portion 44 is provided as a seat for the conductor piece between the lugs 43 like in the first embodiment discussed above. In addition, however, the side walls of the block are narrowed as at 45 in the areas at both sides of the raised portion 44 to engage the respective sides of the seated conductor piece and hold it in a centered position in which its ends are spaced from the walls of the blocks.

The lock bar 38 includes lateral slots 46 and partially completed holes 47 which correspond to these parts in the embodiment discussed above. The slots are modified, however, to the extent that a V-shaped groove 48 is formed in the top of each one, the grooves being designed to serve as guides to assist in the cutting of the lock bar material to the proper length at the time of installation. In lock bar 38 the material surrounding each of the partially completed holes 47 is increased substantially for strength by extending the opposite sides of the bar concentric with the partially completed holes 47. A thin ledge 49 is provided along each side of the top of the bar 38 to extend the overall width thereof and thus increase the space for marking indicia upon the bar.

Assembly is essentially the same as in the embodiments discussed above. The proper number of blocks and conductors are selected, the blocks aligned in side by side relation and the conductors dropped into place in the blocks intermediate the end ones. When in place, the dimples 42 of each conductor piece are engaged over the lugs 43 and the conductor piece 39 thus restrained against longitudinal and lateral movement. In the present instance, the lock bar slots 46 engage in notches 50, which are similar to notch 16, with the bar material surrounding the partially completed holes 47 resting upon top of the conductor pieces as shown in Figure 13. Clearance for the lock bar at the narrowed portions 45 is provided by shoulders 51. These shoulders may be even with, or slightly lower than, the upper-surface of a seated conductor piece. Inasmuch as the ledges 49 rest upon the upper edges of the side walls of the blocks in assembly, the depth of the lock bar from the top to the bottom should be such that the tops of the conductor pieces are also engaged and thereby locked in place. Like in the embodiments of the invention discussed above, once lock bar 38 is in place, all parts are securely fastened together and may be handled and installed as a unit.

Having described my invention I claim:

1. Terminal block construction comprising a plurality of conductor pieces, each of said conductor pieces having provisions at its respective ends for fastening w res v a plural y fiden ic l u it nsula r b acks. each of said bla ks bei g slo ed l ngitu n ly to pro ide a pair of upstanding side walls and a base portion, said walls and base portion defining a seat for a conductor piece, a notch in the upper edge of each of the side walls of each block, the respective notches being aligned tran v rsely of the block, said blocks assembled in aligned side by side relatiomhip with Conductor pieces seated therein, a lock bar, said lock bar having a plurality of equally. spaced transverse slots therein, and

said lock bar disposed lengthwise of the assembled blocks with the bar seated in said notches and with the slots in the bar straddling and engaging adjoining side walls of adjacent blocks.

2. Terminal block construction comprising a plurality of conductor pieces having provisions at their respective ends for fastening wires, a plurality of unit insulator blocks, each of said blocks being slotted longitudinally to provide a pair of upstanding side walls and a base portion, said base portion providing a seat for a conductor piece, and a lock bar, said lock bar having a plurality of slots in the underside thereof arranged to straddle and engage adjoining side walls of adjacent blocks in an assembly of said blocks in which said blocks are placed in side by side relation.

3. A terminal block assembly comprising a plurality of conductor pieces, said conductor pieces being of identical construction and each having provisions at its respective ends for attaching wires, a plurality of unit insulator blocks, each block being slotted longitudinally to provide a pair of upstanding side walls and a connecting base portion defining a seat for a conductor piece, said blocks arranged in an assembly in side by side relation with conductor pieces seated therein, a lock bar having a plurality of transverse slots in one side thereof, said lock bar disposed lengthwise of said assembly with said transverse slots straddling and engaging the adjoining side walls of adjacent blocks in said assembly, and said lock bar between said slots configurated to engage the conductor pieces seated in said unit blocks in locking relationship therewith.

4. A terminal block assembly comprising a plurality of identical conductor carrying unit insulator blocks assembled in aligned side. by side relation, each of said unit blocks having a pair of upstanding side walls, and a lock bar disposed lengthwise of said assembled blocks, and said lock bar having a plurality of slots extending transversely of its underside which are spaced to straddle and engage adjoining side walls of adjacent blocks to locking said blocks in said assembled relation.

5. A terminal block assembly comprising a plurality of conductor pieces having provisions at their respective ends for attaching wires, a plurality of unit insulator blocks assembled in aligned side by side relationship, said blocks being of identical configuration with each block slotted longitudinally thereof to provide a pair of upstanding side walls adapted to receive a conductor piece in slip fit relation therebetween, each of the side walls of a block having a notch centered in the upper edge thereof, and a lock bar, said lock bar having a plurality of transversely disposed slots on the underside thereof, said lock bar seated within the notches in the side walls of the assembled unit blocks with the transverse slots of the bar straddling and engaging adjoining side walls of adjacent blocks in the assembly, and said lock bar being configurated to engage conductor pieces within the blocks when thus seated.

6. A terminal block assembly comprising a plurality of conductor pieces, a plurality of identical unit insulator blocks assembled in aligned side by side relationship, and

a lock bar, each of said insulator blocks being slotted longitudinally to provide a pair of upstanding side walls, said side walls being configurated to receive a conductor piece therebetween in slip-fit relation, said lock bar being disposed longitudinally of said blocks and having means 7 straddling and engaging adjoining side walls of adjacent blocks of the assembled blocks to lock said blocks together and having means engaging conductor pieces disposed within said blocks to lock said conductor pieces in place within said blocks.

References Cited in the file of this patent UNITED STATES PATENTS 2,226,666 Lienzen Dec. 31, 1940 8 Graham Mar. 26, 1946 Labaree Nov. 26, 1946 Pierce Jan. 22, 1952 Latta Dec. 23, 1952 FOREIGN PATENTS Australia Jan. 11, 1943 France Sept. 22, 1930 

